Markets for highly integrated and low power devices require compact and low-power component designs. However, conventional microelectromechanical systems MEMS microphones, like traditional condenser microphones, typically employ bias voltages (e.g., via charge pumps, etc.) to create and maintain the voltage difference between a movable membrane and a stationary electrode. Conventional MEMS microphones do not use electret designs, in part, because suitable dielectric material (e.g., polytetrafluoroethylene (PTFE) or another of a number of plastics or polymers) cannot survive high temperatures encountered in MEMS processes typical of semiconductor fabrication processes.
While some semiconductor electret capacitor designs for microphones have been proposed, such designs have met with limited commercial success, in part because of their retention of PTFE or other plastics or polymers, which limits the availability of semiconductor processes available, which, in turn, can limit the ability of such designs to scale down in size. Another reason for the long felt need for such compact and low-power component designs provided by a MEMS electret microphone is that, because charge pumps can be employed in MEMS devices for a variety of complementary purposes, it is straightforward to use them in conjunction with conventional MEMS condenser microphones.
It is thus desired to provide sensor devices and/or techniques that improve upon these and other deficiencies. The above-described deficiencies are merely intended to provide an overview of some of the problems of conventional implementations, and are not intended to be exhaustive. Other problems with conventional implementations and techniques and corresponding benefits of the various aspects described herein may become further apparent upon review of the following description.